Frank l



F. L. DYER.

SPARK PLUG.

APPLICATION FILED APR. 27. 1917.

n/enva?" FRANK L. DYER, OF MONTCLAIR, NEW JERSEY.

SPARK-PLUG. j

Specification of Letters Patent.

Patented Dec. 16, 1919.

Application led April 27, 1917. Serial No. 164,849.

`To all whom z't may concern:

Be it known that I, FRANK L. DYER, a'

citizen of the United States, residing at Montclair, in the county ofEssex, State of New Jersey, haveinvented certain new and usefulImprovements in Spark-Plugs, of which the following is a specification.

My invention relates to various new and useful improvements in sparkplugs and my object is to improve the construction and facilitate themanufacture ofthe same. rThe.

plug is preferably of the type in which the core within the porcelainmember of the plug is a composite core composed of an upper iron orsteel section and a lower section of a nickel alloy capable of moreeffectively withstanding the high temperatures. The joint between thetwo sections is located within the porcelain member of the plug. Thelower nickel alloy section may itself directly constitute one of theelec'- trodes of the plug or it may carry one or more separatestationary or movable electrodes. In the make-up of spark plugs usingcomposite cores it is sometimes the practice to hold the core inposition by means of a packing of asbestos or similar material but withthis construction the core is not held very firmly and is likely tobecome dislodged and there is always a possibility of leakage around thecore due to the high gas pressures. With other types of spark plugsusing composite cores it is the practice to cement the upper portion ofthe core in place within the porcelain and although with thisconstruction the core will be very rigidly secured within the porcelainwith a gas-tight joint, there is danger of the porcelain cracking underthe effect of heat due to the difference in the co-eflicients of eX-pansion of the core and the porcelain. With my improved spark plug usinga composite core I secure the core very firmly and rigidly in place,always with a gas-tight joint, and at the same time reduce to a largeextent the likelihood of the porcelain cracking, no matter to whatextent the core may expand or contract longitudinally with reference tothe porcelain. Furthermore, in the manufacture of the spark plug Iprovide substantial economies since I do away entirely with the need ofseparately packing or cementing the core in position.

Broadly, my invention consists of a spark plug in which the core isanchored to the porcelain at an intermediate point 1n the bore thereof.rlhis is effected by localizing a very intense heat at an intermediatesection of the core or in a body of hard spelter between the twosections of the core whereby the metal will soften and flowdiametrically so as to form a tight joint with the porcelain thusanchoring the core at an intermediate point within the porcelain with agas-tight joint and permitting the core on either side of the joint toexpand independently of the porcelain to thereby remove any possibilityof cracking the same due to uneven expansion.

While I prefer to make use of my present invention in connection withspark plugs having composite cores as explained. this is not strictlynecessary because the invention` may be carried out in connection withspark plugs having continuous one-piece cores, the latter being reducedat an intermediate portion so as to localize the. heat, permitting themetal to flow at that point and forming a mechanically strong anchoringjoint with the porcelain` all as I will more fully hereinafter describeand claim.

In order that the invention may be better understood, attention isdirected to the accompanying drawing forming part of this specification,and in which- Figure 1 is a sectional view of a spark plug embodying mypresent improvements of the type in which the inner electrode is in theform of a small fan presenting a number of radiating points;

Fig. 2 a similar View showing the parts ready to be assembled before theanchoring joint is formed in the composite core;

Fig. 3 a similar riew showing a modification in which a spelteringaction is performed to produce the joint instead of a, weld as withFigs. l and 2.

In the above views corresponding parts are represented by the samereference numerals.

It is to be particularly noted that in all of these views the spacebetween the bore of the porcelain and the core is-very considerablyexaggerated. Iii actual practice the core will fit the porcelain with afairly easy tit, not allowing any substantial play but providingsuflicient space in which the upset metal may ilow to form the anchoringjoint. 1 is the metal shell of the plug screwed into the engine cylinderand having a gasket 2 holding the porcelain 3 in place in the usual way.This porcelain is provided with a bore which may be of any suitableconstruction. As shown, the upper part `of the bore 4 is of slightlylarger diameter than its lower part 5, so as thereby to form a shoulderbetween the two parts. Carried within the porcelain is a composite corecomposed of a larger part 6 made of iron or steel and a smaller lowerpart 7 made of a nickel alloy. Between the two parts is a joint 8 whichholds the parts rigidly together as one piece and at the same timeanchors the core tightly in position within the porcelain with amechanically strong gastight joint. This joint is formed by electricallywelding the two parts 6 and 7 together, as shown in Fig. Q. Here it willbe observed that the abutting endsof the sections 6 and 7 are somewhatreduced in diameter so as to localize the current and concentrate theheat at an intel mediate point. By applying current to the sections and7 from the transformer 9 thereduced portion of the corewill be heat-edto the welding temperature and by then applying pressure to the twoclamps 10, 10, forcing them inwardly, the welded metal will be upset,forming a tight joint between the coreand the porcelain and at the sametime practically consolidating the two sect-.ions of the core. It willbe understood that in order to reduce the possibility of tracking theporcelain during the welding operation, the porcelain may be firstheated and be in a heated state during the welding operation. Of courseit will be understood that instead of making the core composite asshown, it may be made of a single piece of metal which is reduced indiameter at an intermediate point so as to localize the current and thusbring about the welding of the metal to form the joint between the coreand the porcelain.

In Fig. 3 the operation is the same as above described except that asmall ball 11 of spelter is used, preferably melting at a hightemperature (slightly below the welding point of the core) and offeringsufficient resistance to the current to produce the heating effect.

If desired the section 6 may carry an integral cap 12 which fits overthe upper end of the porcelain so as to give the desired linish to theplug and between said cap and the upper end of the porcelain may beinterposed an asbestos packing 13 which will prevent any possibility ofleakage of gas and at the same time will yield slightly when the coreexpands with yrespect to the porcelain. Above the cap 12 is shown a nut1-1 for making the usual connection electrically to the plug.

Having now described my invention, what I'claim as new therein anddesire to secure by Letters Patent is as follows:

1. An improved spark plug in which the core is provided with a weldedjoint inter-l mediate of its length, locking the core to the continuousone-piece porcelain.

2. An improved spark plug using a composite core in which the twosections of the core are united together by a welded joint which alsofastens the core to the continuous one-piece porcelain intermediate ofits length, substantially as set forth.

3. `In a spark plug, the combination with the continuous one-pieceporcelain member thereof, of a core therein having an intermediatewelded joint locking the same` to the porcelain.

4. In a spark plug, the combination with the continuous one-pieceporcelain member thereof, of a core therein having an intermediatewelded joint locking the same to the porcelain, and an integral capcarried by the core and fitting the end of the porcelain.

5. In a spark plug, the combination with the continuous one-pieceporcelain member thereof, of a core therein having an intermediatewelded joint locking the same to the porcelain, an integral cap carriedby the core and fitting the end of the porcelain, and an elastic packinginterposed between the cap and the end 0f the porcelain.

This specification signed and witnessed this twentyesixth day of April,1917.

FRANK L. DYER. Vitnesses:

A. E. BENTON, J. G. MCDERMOTT.

